Revisiting the migration path to Kyua

[Julio Merino <jmmv%outlook.com@localhost>]

Hello all,

Almost a year ago already (wow... time flies), I imported Kyua into the src 
tree as a replacement for the old ATF tools.  At the same time, I also imported 
some Kyua-based alternatives for atf-run and atf-report, which are compatible 
on the UI side of things but don't behave in exactly the same manner.

All of the above is protected by a MKKYUA knob, which is still set to no by 
default.

In order to make progress on this project, I'd like to change the approach to 
the migration to make it easier for developers and users to test Kyua.

Proposal: make MKKYUA=yes NOT replace atf-run and atf-report with compatibility 
wrappers.  Instead, allow both kyua and atf-run/atf-report to coexist in the 
same installation, and then set MKKYUA=yes by default.  (We'd probably kill the 
import of kyua-atf-compat along the way as well; yay, less code.)

This would allow 1) the continuous testing machines to work just fine without 
any changes to them and 2) it would also allow end users to start playing with 
the new tools without the need to rebuild the system.  We'd then more easily 
and progressively evaluate the change.

Thoughts?  Objections?

Thanks.